Stereoscopic playback is a technology for realizing a stereoscopic viewing by preparing images for two or more view points. Although the stereoscopic display can be realized by various methods, the basic principle is to cause the left eye and right eye of a viewer to see different display images so that a pseudo stereoscopic image is created by the parallax between the eyes.
For example, one stereoscopic display method uses shutter glasses. In this method, respective display images for the left and right eyes are updated at a high speed. The shutter glasses are controlled to block views of the left and right eyes alternately in synchronization with the update timings. With this arrangement, the images for the left eye are viewed only by the left eye, and the images for the right eye are viewed only by the right eye.
Currently, a mainstream playback of a stereoscopic video stream is in the movie theaters, but in the future, the playback of a stereoscopic video stream on a home playback device will become popular as well.
Especially, package media, which are recording media for over-the-counter sales of movies or the like, contain not only video images but also background images, subtitles, and drawing images on respective separate planes, and display devices can display an image in which they are all superimposed. Thus by presenting each of the background images, subtitles, and drawing images stereoscopically, it is possible to realize a highly interactive stereoscopic playback. Of these, the video images and subtitles are displayed clearly without flickering since they are played back in synchronization with the image output signals of the playback device in units of frames.
Accordingly, when a video stream in a package medium is to be played back stereoscopically, it is necessary for the video stream to have been encoded at a rate of, for example, 120 frames per second. Other methods for providing the stereoscopic effect include realizing the stereoscopic viewing by the “side-by-side” method recited in Patent Literature 1 identified below.
Also, Patent Literature 2 identified below discloses a method using a checkered pattern.
Furthermore, Patent Literature 3 discloses a technology for displaying the screen stereoscopically in which a 3D image is created by extracting the number of objects from 2D images, creating as many layers as the extracted number of objects, and changing the depth of each layer.
[Citation List]
[Patent Literature]
[Patent Literature 1]
PCT International Publication No. WO2005/119675 Pamphlet.
[Patent Literature 2]
U.S. Patent Application Publication No. 2008/0036854 Specification.
[Patent Literature 3]
U.S. Patent Application Publication No. 2002/0118275 Specification.
[Non-Patent Literature]
[Non-Patent Literature 1]
“Foundations of the stereoscopic cinema”. Lenny Lipton.